Use LBI/LBO to Enable a TPS62056 or TPS61092

user4451984

Other Parts Discussed in Thread: TPS62056, TPS61092, TPS62065, TPS62051, TPS62125

Hi, I want to disable a TPS62056 or TPS61092 when the input voltage drop below 2.7V. My question is if I set correctly the voltage divider for the LBI pin, it should drive the LBO pin low when the voltage is low enough. Can I use the signal from the LBO to shout down the regulator ? I have attached the schematic so you can understand better.

Thanks

Riccardo

over 9 years ago

0 Jasper Li over 9 years ago

TI__Mastermind 46905 points

TPS61092 is boost converter and TPS62065 is buck converter. they are totally different device.
may i konw what is the input voltage range and output voltage .

0 user4451984 over 9 years ago in reply to Jasper Li

Intellectual 850 points

They are different devices but the LBI and LBO should work in the same way, isn't it ? Can I use the schematic for the TPS62056 ?

0 Chris Glaser over 9 years ago in reply to user4451984

TI__Guru**** 150930 points

No, per the D/S the LBI/LBO circuit is disabled when EN is low. You need to use the TPS62051 with the enhanced LBI functionality to do what you want.

But these are both very old ICs. Why not use a discrete SVS and newer ICs? The total solution will be much smaller.

As well, TPS62125 has an enable comparator which does the functionality you need.

0 user4451984 over 9 years ago in reply to Chris Glaser

Intellectual 850 points

Thanks for your response. Just another question, when the voltage on the LBI pin is low enough is the regulator shut down ? Or the LBI pin control just the LBO output ?

0 Chris Glaser over 9 years ago in reply to user4451984

TI__Guru**** 150930 points

This should be explained in section 9.3 of the D/S. This is the difference in the standard and enhanced versions. Did you read this already?

0 user4451984 over 9 years ago in reply to Chris Glaser

Intellectual 850 points

Thanks

0 user4451984 over 9 years ago in reply to Chris Glaser

Intellectual 850 points

I have read the datasheet of the TPS62125 and I have a question. The input range is 3V to 17V but the VUVLO is 2.8-2.9V, I don't understand if it is safe have a Vin of 2.8 V .

0 Chris Glaser over 9 years ago in reply to user4451984

TI__Guru**** 150930 points

Per note 1 there, the IC operates down to the UVLO level (wherever that occurs). This is ok for the IC.

0 user4451984 over 9 years ago in reply to Chris Glaser

Intellectual 850 points

Thanks. Just one more question about LBO. on the figure 5 (PAGE 9) of the TPS6205x datasheet. I want to use a TPS62051 and disable the device under 3.5 V,. I don't need hysteresis or check LBO with a microcontroller. Can I connect LBO to ground and avoid to use R7 and R4 ?

Thanks

0 Chris Glaser over 9 years ago in reply to user4451984

TI__Guru**** 150930 points

Yes, this is mentioned at the end of page 8.

Power management

Power management forum

Use LBI/LBO to Enable a TPS62056 or TPS61092